This disclosure relates to a fracturing system and method for acquiring oil and gas.
The demand for natural gas and oil has significantly grown over the years making low productivity oil and gas reservoirs economically feasible, where hydraulic fracturing plays an important part in these energy productions throughout the world. For several decades different technology has been used to enhance methods for producing resources from oil and gas wells. Long horizontal wellbores with multiple fractures is one commonly used process to enhance extraction of oil and gas from wells. This process starts after a well has been drilled and the completion has been installed in the wellbore. Multi-stage hydraulic fracturing is a method that involves pumping large amounts of pressurized water or gel, a proppant and/or other chemicals into the wellbore to create discrete multiple fractures into the reservoir along the wellbore.
One of the technologically advanced methods being used today is simultaneous proppant fracturing of up to thirty fractures in one pumping operation. This method involves usage of proppant to prevent fractures from closing. However, this practice can usually cause an uneven distribution of proppant between the fractures, which will reduce the efficiency of the fracture system. As a result, this practice can also cause fractures to propagate in areas that are out of the target reservoir. Thus, such method can be inefficient and unsafe.
Additionally, proppant fracturing usually involves multiple steps and requires several tools in order to be performed successfully. Such practice that will allow even distribution of proppant between fractures highly depends on setting, plugs between the fracture stages or using frac balls of increasing sizes. In these methods, plugs are either set after each fracture has been perforated and pumped, or frac balls are dropped from the surface to successively open fracturing valves placed along the well. For each stage, balls of different diameters are dropped into the well corresponding to a specific fracturing valve's seat. At a point in the well, the ball will no longer pass through due to a decrease in well diameter. Once the ball is in place, fracturing can take place. After fracturing, the plugs must be drilled out and the balls must be recovered. With each fracturing stage while setting plugs, much time and energy is expended in tripping out of the hole between the stages and drilling out the plugs. Moreover, land-based rigs are usually rented per day basis, and so any delays can be quite expensive. Also, only about 12 different fracture stages are possible with the ball method before a restriction in flow area due to small ball diameter, which makes fracturing difficult due to large pressure losses.
As such it would be useful to have an improved system and method for fracturing oil and gas wells.